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(c) 2017 beyondbenign - All rights reserved.

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Presentation on theme: "(c) 2017 beyondbenign - All rights reserved."— Presentation transcript:

1 (c) 2017 beyondbenign - All rights reserved.
Fabulous Fabrics Questions in Context: Do you remember something better when you are asked to think about it? On the right, in the conversation bubble outlined in yellow, are guiding questions that you should ask the students during the associated step. Each question should be asked separately – and a short amount of time should be allowed for responses. Image: Emma Jane Hogbin/Creative Commons Steps, Content & Hints Main directions and content for the activity are in the boxes to the left with the orange border, like this one. In a classroom setting, you will lead the students through the activity with a series of questions, the students’ own responses and brief explanations. Whenever possible, find and affirm what’s right about the students’ answers. (c) 2017 beyondbenign - All rights reserved.

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Green Chemistry Introduction: Defining Green Chemistry Have students work in pairs for 30 seconds to come up with a definition for green chemistry. Break down the meaning of both words. Establish that chemistry is the science of making products. Eco-friendly, good for the environment, sustainable. What is Chemistry? What does chemistry mean to you? Do you think of good things or bad things? Who has heard of companies going green? What does that mean? Chemists make “stuff,” like materials and medicines. Green chemistry is pollution prevention at the molecular level, the basic design stage. So what is it that green chemists do? What do Chemists do? Use wait time. Build off of their prior knowledge. Acknowledge student responses and prompt them for more information. Control the conversation by asking for a certain number of answers. Chemists are inventors. They help to design just about every product out there. Traditionally chemists were not taught about the environmental impact or toxicology. We have had many advances and helpful inventions but we have also had inventions that have caused harm to the environment. Green chemists design products taking into account the entire process, energy efficiency, renewable resources, the product itself along with the end-of-life impact of the product. Is there anything in this room that a chemist invented? What about the desks, paint, floor, etc. Who has taken medicine? Does anyone use an iPod or an mp3 player? What about a computer or a cell phone? Set the Scene: Connect the Dots & Introduce the Activity Topic Connect the dots for them: they are the future scientists who will help to discover and invent the solutions to the environmental challenges. Today we will be working with fabrics. Where do fabrics come from? Do you know what your shirt is made of? Turn to your partner and check the tag of their shirt. Let’s list the different materials. (c) 2017 beyondbenign - All rights reserved.

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How are fabrics made? What happens to a fabric when you’re done with it? Hold off answering all these questions – you’re setting up to do the life cycle cards! Let’s talk about fabrics! Think about where fabrics come from. What do we think of when we hear the word “natural”? What do we think of when we hear the word “synthetic”? Some fabrics are made of natural materials, that come from nature. Other fabrics are made from man-made materials. We call these types of materials “synthetic”. What other things can you think of that are made from natural materials? How about from synthetic materials? Life cycle cards Divide your group into smaller groups. Each group will be given a set of cards. Within the stack of cards are the steps to two different life cycles, one for polyester fabric and the other for cotton. Each group will work together to separate the cards based on which fabric they belong to and then put them in order based on the life cycle. When the groups have finished, you will bring the groups back together and go over what they have come up with together. When you have finished going over the order of the cards, use some of the questions to the right to help start the conversation about sustainability, green chemistry, and fabrics/textiles. Which of these two fabrics is synthetic? Which is made of natural fibers? What are the big differences between the cotton and the polyester life cycles? What are the similarities? What is an advantage that cotton has over polyester? What is an advantage that polyester has over cotton? Is one of these fabrics better than the other? Why or why not? (c) 2017 beyondbenign - All rights reserved.

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When would I want to wear this shirt? How do you know? What types of properties does this shirt have that make it appropriate for its job? What properties do all three of these shirts have in common? Choosing a fabric If you want to design a shirt, how are you going to decide what type of fabric to use? Discuss as a group! You should have three different types of shirts with you: one meant for looking nice (like a blouse or a button down shirt), one athletic/quick drying shirt, and one sweatshirt or sweater meant for warmth. Compare and contrast the three shirts with your group. Ask the group if there are any special properties that a green chemist may consider when looking at fabrics to use. How do manufacturers make decisions about which fabric to choose? Remember the 3 keys for green chemistry. The challenge! The unique properties of different materials can be used to help us make decisions when designing new products. These properties can also help us identify unknown samples! Each set of partners will be given a piece of unknown fabric. The goal is to determine what type of fabric it is! Each group will be given: 2 Unknown fabric samples 2 Multi-fiber ribbons Multi-fiber ribbon answer key Magnifying glass Ask each pair to see if they can identify their unknown just by using the magnifying glass and the multi-fiber ribbon. Have them mark their best guess on the paper key for the multi-fiber ribbon with a #1. Ask how many of the groups are confident in their hypothesis. Ask one of these groups to share why they are not confident in their first guess. What makes it hard to tell the fabrics apart? Are there any of the fabrics that you can tell just by looking at them? (c) 2017 beyondbenign - All rights reserved.

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Dyeability as a property of fabric Reflect with the group and discuss if there are any properties that those three shirts have in common. Help your group understand that all three fabrics have been dyed and that how a fabric interact with dye can be considered a property of that fabric. Ask the group how this property might help them identify their unknown fabric. Each group is given a container with red Kool-Aid. Cherry Kool—Aid is one of the standard stains that is used in industry when companies want to stain fabrics, like when they test how well a laundry detergent works. Materials for each group Container of cherry Kool-Aid Stirring rod or plastic fork (for lifting fabric out of dye) Paper towels Each group places one of their unknown samples and one of their multi-fiber ribbons into the Kool-Aid and allows it to dye for 3-5 minutes. While the fabrics are dyeing, elaborate on how important color is when we’re choosing fabrics for different things. A few ideas to facilitate discussion: Ask students to count how many different colors they are wearing at the moment Ask partner pairs to see how many different objects in the room they are in have fabric on/in them Have students share what they have observed with the group, emphasizing how much of our world is made up of fabrics. What are the challenges with trying to identify the undyed unknown fabric? How might dyeing the fabric make it easier or harder to identify the unknown? How many of you have ever bought something because you liked the color? How many did NOT bought something because you didn’t like the color? Can you think of any examples of clothing when color matters for more than just the personal preference of the person wearing it? Examples – sports teams, business clothing, school uniforms, etc. (c) 2017 beyondbenign - All rights reserved.

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Checking their hypothesis Have students take their unknown and their multi-fiber ribbons out of their dye and place them on the paper towel. Ask groups to look back on their initial guess as to the identity of their unknown. Does what they see now support that guess? Do they want to change their hypothesis? Have students make a note of which fabric they now believe their unknown to be by writing a #2 next to their new hypothesis on the fabric strip key. Invite students to share their observations. Does comparing the dyed strip to your unknown confirm anyone’s original hypothesis? Have any of you changed your hypothesis now that you’ve seen how the fabric has dyed? pH as a factor in dyeing Ask if any of the students are still not 100% confident in their hypothesis. Let’s think about dye. What happens when we make Kool—Aid? Kool-Aid powder dissolves in water to make Kool-Aid drink. When the powder (the solute) is dissolved in water (the solvent), it makes a solution. One of the ways to characterize solutions is by using pH. pH is a scale that determines if a solution is acidic or basic. Solutions with a pH above 7 are categorized as basic and those with pH below 7 are acidic. Our Kool-Aid dye is either acidic or basic, so we now know how fabrics will dye in one of these types of solution. If we can identify if our Kool-Aid is acidic or basic, we’ll be able to determine what we need to do to dye our second set of fabrics samples in the opposite. For example, if we already have looked at our fabrics in basic dye, we’ll want to dye them in acidic dye. For those hard to identify fabrics, looking comparing their dyeability in both acidic and basic dyes will give us another layer of “data” to use to help us draw a solid conclusion. Have any of you ever made Kool-Aid? What happens when you add Kool-Aid powder to water? What makes dye a solution? What are some different properties of solutions? Can any of you tell me anything you’ve ever eaten that is acidic? How about basic? (c) 2017 beyondbenign - All rights reserved.

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Changing the pH of the dye Each group should get Litmus paper Ammonia Vinegar Explain the litmus paper test. Blue = basic, red = acidic. They need to use the litmus test to determine if their dye is acidic or basic. Once they’ve determined that the Kool-Aid is acidic, they need to determine what they need to add to change the Kool-Aid from acidic to basic. To do this, they’ll repeat the litmus test on both the vinegar and the ammonia. Explain to them that they need to choose which solution they need to add to their dye to make the switch. Once they determine that they need to add ammonia, encourage them to add about 5 ml at a time, stir their dye, and repeat the litmus test until their dye is basic. Once their dye is basic, they can add their second unknown sample and multi-fiber ribbon to their dye. Allow this to dye for about 3-5 minutes. As the fabric is dyeing, revisit natural vs synthetic. Have partners look at their fabric keys and decide which fibers are synthetic and which are natural. Then, have the students look back at their acid-dyed strips and make observations about how natural vs synthetic fibers dyed in the first round. Have them make predictions for how the two types of fabrics will dye in the basic-dye. After 3-5 minutes of dyeing, have the students take out their samples from the dye and place them on a paper towel. Have them check their hypothesis one more time, and note on their fabric key with a #3. Ask students to share if any of them changed their hypothesis and why. If none changed their guess, ask the group what observations they have about the basic dye vs the acidic dye. Do you expect Kool-Aid to be basic or acidic? Why? What do you expect will happen when you dye the fabrics in the basic dye? Which fabrics are synthetic? Which are from nature? How did you decide? Is there any pattern when you look at how the acid-dye worked with either the natural or the synthetic? What do you see? Do you think either the natural or synthetic fibers will dye better in the basic dye? Why do you think so? (c) 2017 beyondbenign - All rights reserved.

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If you were a green chemist, which fabric would you want to use to make t-shirts for your science club, class, etc? Which one would you not want to use? Why? Wrapping it up Review what makes something a green chemistry technology. Discuss as a group which fabric a green chemistry might be most likely to choose if they were going to make t-shirts for a group. In closing, reflect on the activity. Discuss whether or not fabrics and textiles are simple in terms of green chemistry. Reiterate the 3 criteria of green chemistry (safety, cost and performance). Great Job! Scientists ask hard questions and seek out answers. Fabrics aren’t an easy conversation, but the best way to improve them is to ask questions about where they come from and how they’re made! Reinforce how green chemistry is the science of solutions and how green chemistry can help make fabrics and dyes better for human health and the environment. Are fabrics easy to categorize as “green” or “not green”? What about fabrics make them hard to categorize? Who here asks questions about how products are made or why we have certain problems? Sounds like we have some green chemists in the room. Who thought that this was easy? Who had fun doing this? Do you think that science is something that you can do? In Closing: Green chemistry provides the tools needed for creating solutions to environmental challenges. As a green chemist you can be a part of the solution by inventing better technologies for the future. Also remember that you do not need to be a scientist to make a difference in this world. As an informed citizen you have the power to influence change with your decision making, voting power and purchasing choices. Any questions? Wrapping up is always a good time to talk a little more about why you are in the classroom, what you are studying, researching or pursuing as a career. (c) 2017 beyondbenign - All rights reserved.


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